Series S2A Synchro options

[texrover]

Hello all; long time lurker, first time poster.

I've sold my D90 and looking to break open my long overdue '71 S2A project. The first thing that I'd like to focus on (once I get it to move into the garage) is the possibility of adding synchro gears.

Can I rebuild the existing box with S3 gears?
If that's not an option or it would be easier to swap an S3 box, what should I look for? Any suffix?

I might consider a newer conversion but would look at the simplest options first.

Thanks in advance!

[Ren Ching]

Yes, you can do it since you should have the later suffix IIa box that uses the larger layshaft bearing. You should check to make sure you have the right gearbox for your truck. I forget what suffix that feature started with but that info is easily found on the lrfaq.org site.

That said, it might be eaiser to start with a SIII box and put your bellhousing on it. You will need all the innards of the SIII box, the only thing that can swap over is a few of the bearings, the 3/4 synchro, and some of the shifter and shift selector parts. It is a nice setup that gives you the improved driveability of the SIII box combined with the robust IIa throwout bearing setup.

I have this setup in my 109. Nice to have the top fill on the gearbox.





Hello all; long time lurker, first time poster.

I've sold my D90 and looking to break open my long overdue '71 S2A project. The first thing that I'd like to focus on (once I get it to move into the garage) is the possibility of adding synchro gears.

Can I rebuild the existing box with S3 gears?
If that's not an option or it would be easier to swap an S3 box, what should I look for? Any suffix?

I might consider a newer conversion but would look at the simplest options first.

Thanks in advance!

[texrover]

Thanks Ren, good point on the throwout; I forgot about that!

Know any links that give me some specifics on the bits and pieces I should keep?

[evilfij]

Why do you want a synchro 2nd?

[texrover]

never been much for double clutching...

[Troys]

Jason;

I just rebuilt a Series III Type C gearbox and installed my Series IIa bell housing as to retain the current clutch slave and throw outbearing set for my 1966 Series IIa.

Series III trannies are failry easy to come by. You can purchase this set up from suppliers as well asa rebuit unit. I wanted to do a rebuild so I could learna bit. I went through the trannyand only replaced what really needed replacing. I did replace all the bearings and seals.

Troy

[Ren Ching]

don't know of any links.

just off the top of my head, you will need to change:

layshaft
mainshaft
mainshaft gears (maybe you can keep 3rd gear, not sure)
manishaft bushings (except for the 2/3 bushing but you will want to change that regardless)
reverse gear (i think, not sure)
selector forks (i think, not sure)

you will get to keep:
3/4 synchro
primary pinion
constant speed gear
layshaft bearings
mainshaft bearings
bellhousing
throwout bearing housing and assy.
selector shafts
drain plug
shift lever
main gearbox housing and top cover

I would think you should change all bearings, seals, synchros, bushings, thrust washers, circlips etc as a matter of course.

Thanks Ren, good point on the throwout; I forgot about that!

Know any links that give me some specifics on the bits and pieces I should keep?

[texrover]

great stuff guys! thanks! off to Florida for the week and will try to catch up this weekend and post any questions if i have any.

i'm sure i'll come up with a million more questions beyond just the tranny....